# Binary Addition - 2's Compliment Representation

1. Sep 6, 2016

### Marcin H

1. The problem statement, all variables and given/known data

2. Relevant equations
Binary Arithmetic

3. The attempt at a solution
Is this the right way to do these problems? If I see a binary 1 at the beginning of the binary number do I just do the 2's compliment of that and add them? I am not too sure what it means by assume numbers are represented in 2's compliment. How do I add them exactly?

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2. Sep 6, 2016

### Staff: Mentor

You did the 2nd part of problem 1. You still need to do the first part of this problem, and both parts of the other four problems.

For the 1st parts of the five problems, the assumption is that they are all unsigned numbers, so you would add them as you normally would binary numbers. As an aside, 8-bit unsigned numbers have a range of 0 through 255 in base 10. Signed 8-bit numbers have a range of -128 through 127, base 10.

For the 2nd parts, the assumption is that they are unsigned numbers. A number with a 1 in the highest bit represents a negative number. If the highest bit is 0, the number is positive or maybe zero.

3. Sep 7, 2016

### rcgldr

You just add the numbers. The actual addition of unsigned and 2's complement numbers produces the same result, with the only difference in the detection of a carry for unsigned numbers or overflow for signed numbers.